Grant Fox has revealed that the All Blacks will consider not picking a third first five-eighth in their Rugby World Cup squad.

All Blacks selector Fox, a test great who was part of the 1987 World Cup triumph, said the selectors already have a plan in mind for how they will cover for the loss of injured utility back Damian McKenzie.

While he didn't want to divulge specifics, Fox noted that the tournament being hosted relatively close to New Zealand, in Japan, could play a part in their thinking of how to replace McKenzie, a specialist first five-eighth and fullback.

"The way the draw sits, will a first five get a lot of rugby anyway?," he asked when quizzed about the issue on Radio Sport.

"Possibly not. Japan is only ten and a half hours away, it's not hard to get someone up there."

Chief player Damian McKenzie was injured against the Blues. Photo: Getty Images

McKenzie's absence has led to a lot of debate as to how the All Blacks should approach their third first-five spot, with no standout candidate amongst the Kiwi pivots currently playing in Super Rugby.

NZME understands that Aaron Cruden is considering returning from France for the end of the 2019 Super Rugby season, and the 2020 season, with the Chiefs - making him a potential candidate for a shock World Cup call-up.

There is another school of thought that the All Blacks could get away with using a utility player as an emergency first-five option, such as Jordie Barrett or TJ Perenara.

Fox said that was a possibility as the selectors analysed the balance of their likely squad.

"You need someone (at first five-eighth) to cover those middle two pool games (Canada, Namibia). Could we get away without a specialist? Possibly.

"Is that risky? Yes. We can only pick 31 so you've got to compromise somewhere. Do we compromise at 10, 9 or somewhere else?"

Fox said it had to be remembered that if a top player was replaced because of injury, he would be ineligible for the rest of the tournament.

"We are pretty clear on thought at the moment but it's something we don't want to divulge too much," he said.

"You've got to worry about your injuries...if you get a late injury before a big game you are running a hell of a risk.

"Compromise and risk becomes part of your discussion and we've just got to deal with it. But it is a lot easier to get a player to Japan if needed compared to the UK in 2015."